Abstract : This paper describes a recent experiment conducted with Patriot air defense officers and using the Patriot air defense simulators at Fort Bliss, Texas. The experimenters found that, under certain conditions, the participants made different identification judgments and took different engagement actions depending on the sequence in which the same information was presented to them. This finding was consistent with theoretical predictions regarding how operators process information, and the hypothesis that their processing approach (or Heuristic) would result in biased judgments under certain conditions. Future research is directed toward investigating whether display modification can remove the observed judgmental bias. Generally, this experiment demonstrates the applied implications of basic research investigating human information processing, and the importance of understanding cognitive processes when developing computer systems. (KAR) P. 3